Manufacture of alkylated sulphonic acids and esters



Patented Oct. 15, 1935" UNITED STATES- MANUFACTURE OF ALKYLATEDSULPHONIC ACIDS AND ESTERS Robert M. Isham, Okmulgee. Okla assignor ofthree-fourths to William B. Pine, Ohnulgee,

Okla.

No Drawing.- Application April 6, 1934, Serial N- 719,412

13 Claims. (Cl. 260-99.10)

This invention relates to a method for the preparation of alkyl estersof alkylated and sulphonated aromatic bodies.

It is an object of the invention to provide a novel method for theproduction of esterified, alkylated and sulphonated aromatic bodies bythe direct union of olefins therewith.

Another object is to provide a novel method for the sulphonation,alkylation and esterification of aromatic hydrocarbons by a singlereaction.

A further object is to provide a novel method for the alkylation and.esterification of sulphonated aromatic bodies by the direct union ofolefins therewith.

A further object is to provide a method whereby a sulphonated aromaticbody may be first alkylated by direct union with an olefin andthereafter esterified if desired by direct union with the same or adifierent olefin.

The invention may be employed for the production of derivatives of avariety of aromatic hydrocarbons including for example polycyclic bodiessuch as naphthalene and anthracene and monocyclic bodies such as benzeneand toluene.

The alkyl groups which it is desired to introduce into the aromaticnucleus and to combine with the sulphonic group are provided by usingthe proper olefin or mixture of olefins such as propylene, amylene,etc., or mixtures thereof. These olefins may be employed in the purestate, either separately or as mixtures of pure olefins as may bedesirable, or olefin-bearing gases from any suitable source may beemployed provided no large amount of aromatic bodies is present. Forexample, pressure still gas from oil refineries and cracked gasolinecontain large amounts of olefins and can be employed in the process asstarting materials.

Where the starting material is naphthalene or other aromatic body theprocess may be carried out in such a manner as to include sulphonationtogether with alkylation of the aromatic nucleus and if desired byesterification, and in most cases it will be preferred to carry outthese reactions in a single step, although a plurality of separate stepsmay be employed if desired. Where the sulfonic acid is readily availableas a starting material, however, the sulphonation is unneces- 50 sary.If desired, the process may stop with the alkylation of the aromaticnucleus so as to provide an alkylated sulphonic acid, or it may becarried further to include esterification of the acid, or in someinstances the reaction may be 55 so carried out that the acid is onlypartly ester;-

' group, and in such cases it will be desirable in the interest ofsimplicity and economy to carry out the entire process in a singlereaction, using 10 only one olefin or mixture of olefins orolefinbearing material. When mixtures of olefins are employed thereaction product may vary both as to the alkyl groups which areintroduced in the nucleus and as to those combined with the sul- 15phonic acid group. However, if desired, the process may be carried outin steps in such a way that the alkylation of the aromatic nucleus isseparate from the esterification, so that particular olefins ordifferent olefins can be employed in the separate steps.

In general, the procedure consists in prepar ing a mixture of thedesired aromatic hydrocarbon, sulphuric acid at least sufficient tosulphonate the hydrocarbon and produce the desired sulphonic acid,preferably a quantity of an inert solvent for the hydrocarbon and olefinsuch as a light fraction of gasoline or some previously preparedester,.and the olefin or mixture of olefins which it is desired toreact. When these reagents are brought together, a vigorous reactiontakes place with evolution of. heat, and when the absorption of theolefin ceases it is found that sulphonation, alkylation of the nucleusand esterification have all taken place. The resulting product comprisesprincipally alkyl esters of a1- kylated aromatic sulphonic acids, butmay also contain a certain quantity of alkylated hydrocarbon which wasnot sulphonated. For some purposes, however, the presence of somealkylated but non-sulphonated hydrocarbon is not ob-- jectionable.

In case quantities of a suitable aromatic sulphonic acid are readilyavailable as a starting material, the reaction may be carried out insub-,7 stantially the same way except that sulphuric acid is unnecessaryin order to carry out the sulphonation described above. In this case thesulphonic acid is preferably mixed with a quantity of the solvent andreacted with the desired olefin or mixture of olefins as hereinafterdescribed, with formation of alkyl esters of the alkylated andsulphonated aromatic hydrocarbons.

The conditions under which the reaction takes place are subject toconsiderable variation. In general, the mixture should be agitatedduring the reaction in order to insure thorough mixing of the reagents.The olefin may be added in any suitable manner, either as a gas orliquid depending on the specific olefin or olefins employed and thetemperatures used for the reaction. It has been found that excesssulphuric acid acts as a carrier or catalyst and accelerates thereaction so that it may be carried out at room temperatures. Hence it isdesirable in many cases to employ an excess of sulphuric acid over thatrequired for sulphonation, or when sulphonic acid is available as astarting material, to add. a small quantity of sulphuric acid for thispurpose. The use of sulphuric acid as a catalyst is unnecessary,however, if a temperature of C. to C. is maintained during the reaction,as under these conditions the alkylation proceeds substantially tocompletion and then is followed by esterification. The reaction in thecase' of mono-cyclic aromatic bodies is somewhat slower than withpolycyclic bodies and hence it is desirable when treating mono-cyclicbodies to take advantage of the ascelerating action of sulphuric acid aswell as to raise the temperature somewhat, say to 50 C.

A wide variety of solvents may be employed, provided they are inertwith, respect to the desired reaction. The action of the solvent isprobably physical, the olefin being dissolved as well as the aromatichydrocarbon or sulphonic acid and the contact between the reagents beingthus improved. A quantity of alkylated ester from a preceding operationmay be employed as these esters are good solvents for the sulphonicacids and for the aromatic hydrocarbons. Other solvents such as a lightfraction of gasoline may also be' used. The amount of solvent employedis not critical and may vary widely.

The reaction product, in addition to the esters referred to above, maycontain some sulphonic acid which has not been esterified, as well assulphuric acid and a quantity of water produced by the sulphonationreaction. The mixture is washed with water to remove any excess freeacid, and the gasoline or other solvent may be separated from themixture in any suitable way as by distillation.

The amount of olefin to be employed may vary considerably depending uponthe extent to which the alkylation and esterification reactions are tobe carried. As stated above, it has been found that the alkylation ofthe aromatic nucleus largely precedes the esterification of thesulphonic group. Hence by observing the acidity of the reaction mixtureas the reaction proceeds, the progress of the reaction can be followedand the process may be controlled as to the results produced. Forexample, when. it is observed that the acidity of the mixture hasdisappeared, the alkylation and esterification reactions have beensubstantially completed, unless excess sulphuric acid is used as acarrier or catalyst. In the latter case, the reaction will besubstantially complete when the acidity of the mixture has beendecreased to the point corresponding to that portion of the originalacidity supplied by the excess sulphuric acid. If mixtures of acids andesters are desired, the reaction may be stopped before proceeding tothis point.

Further, since as stated above, theallgvlation reaction takes placebefore esterification, the completion of alkylation is substantiallyindicated by the point at which the acidity of the reaction mixturebegins to decrease. If the addition of olefin is stopped at this point,the resulting product will comprise substantially only 8.1- kylatedsulphonic acid without esteriflcation. These acids, as distinguishedfrom their esters, 5 may be desirable for certain purposes. A furtherstep may then be carried out if it is desired to introduce one or morealkyl groups in the nucleus and a difierent group or groups in thesulphonic acid group. In this case the desired olefin is in- 10 troduceduntil the alkylation is completed as indicated by the initial decreasein the acidity of the reaction mixture. The treatment with olefin isthen discontinued and the .alkylated sulphonic acid recovered from themixture andthereafter 15 converted to an ester by treatment with anotherolefin.

As an example of the process, 300 grams of naphthalene was added to 1000cc. of a light gasoline fraction and 300 grams of sulphuric acid (spe-20 cific gravity 1.84). This mixture was agitated with addition ofpropylene gas until 480 grams of propylene had been absorbed. Thereaction was vigorous with much evolution of heat, and the reactionproduct-consisted of a mixture of propy- 2.; lated naphthalene sulphonicacids and their esters and a certain amount of naphthalene which hasbeen propylated but not sulphonated, together with excess sulphuricacid, gasoline and water produced by the sulphonation reaction. 30 Thismixture was washed with water for the removal of the excess sulphuricacid and then distilled to distill off the gasoline.

In another example, 300 grams of naphthalene sulphonic acid was agitatedat room temperature 35 with 200 cc. of a light gasoline fraction and 40grams of concentrated sulphuric acid (specific gravity 1.84) at roomtemperature and propylene gas was added until the total acidity of themixture corresponded to that portion of the original 40 acidity suppliedby the sulphuric acid. The heavier acid layer was largely dissolved bythe gasoline as the reaction proceeded. The mixture was washed withwater for removal of free acid and the gasoline was distilled off,leaving a mixture 5 of esters consisting largely of isopropyldi-isopropyl naphthalene sulphonate. The product was a light brownviscous oil somewhat heavier than water.

In a variation of the second example stated 60 above, the treatment withpropylene was discontinued as soon as the acidity of the mixture beganto decrease, and the mixture was then treated with water and thepropylated sulphonic acid recovered from the water layer. This pro- 55pylated naphthalene sulphonic acid was then converted to an amyl esterby treatment with amylene in a similar manner. During the first step asmall amount of isopropyl ester was formed, which was recovered from thegasoline 60 layer.

It will be observed that the method described above can be used toproduce either the alkylated acids or the esters of those acids. Thuswith naphthalene sulphonic acid and propylene there 65 may be obtainedthe isopropyl esters of .mono, di, tri, etc., isopropyl naphthalenesulphonic acids, or if desired the unesterified acids; Similarly, withamylene and naphthalene sulphonic acid, there may be obtained the amylesters of a se- 70 ries of amyl sulphonic acids, or the acidsthemselves, and with mixed olefins there may be obtained mixtures inwhich the alkyl groups vary. both those attached to the sulphonic groupand those attached to the naphthalene or other aromatic nucleus. Also,by exercising proper control, the nucleus may be alkylated with oneolefin, for instance amylene, and thereafter the alkylated acid may beesterified with another olefin, for instance propylene. The method asfirst described above provides a very simple way of forming the desiredfinal products directly from the aromatic hydrocarbon and the olefin ina single step. However, if sulphonic acid is available, it may beemployed as a starting material if desired according to the procedureindicated. The use of the solvent renders the sulphonic acid more mobileand also aids the reaction in the case of gaseous olefins by dissolvingthe olefin and thus improving its contact with the acid.

It will be understood that the invention is not limited to the specificexamples given above and that changes may be made in the startingmaterials, their proportions, and details of the procedure withoutdeparting from the spirit of the invention. Thus the olefin and thearomatic body to be used may vary depending on the materials availableand the uses to which the product is to be put, and the proportions ofthe materials may likewise be varied as will be apparent to thoseskilled in the art. Furthermore, the starting materials are not limitedto the simple aromatic hydrocarbons mentioned above, but include alsosubstituted derivatives such as phenols, chlorinated and nitratedcompounds, etc. These derivatives may be alkylated, sulphonated andesterified in the manner described above to produce a variety ofproducts, such as alleviatedalkoxylated-sulphonate esters from phenols,chlorinated alkylated sulphonate esters from chlorinated compounds, etc.Reference will therefore be had to the appended claims for a definitionof the limits of the invention, and the term aromatic bodies as used insaid claims will be understood as including substituted derivatives aswell as simple aromatic hydrocarbons.

What is claimed is:

l. A process for producing alkyiated sulphonated and esterified aromaticbodies which consists in reacting an aromatic body with a sulphonatingagent and an olefin in the presence ofan inert solvent for said aromaticbody and olefin to sulphonate and alkylate said aromatic body andcontinuing the treatment with olefin to esterify the sulphonic acidgroup.

2. A process for producing alkylated sulphonated and esterified aromaticbodies which consists in reacting an aromatic body with sulphuric acidand an olefin to sulphonate and allgylate the aromatic nucleus andcontinuing the treatment with olefin to alkylate the sulphonic acidgroup.

3. A process for producing alkylated sulphonated and esterified aromaticbodies which consists in reacting an aromatic body with sulphuric acidand an olefin to sulphonate and alkylate the aromatic nucleus andcontinuing the treatment with olefin to alkylate the sulphonic acidgroup, the sulphuric acid being in excess of the amount required toproduce the mono-sulphonic acid.

4. A process which consists in reacting an aromatic body with sulphuricacid and an olefinto sulphonate and alkylate the aromatic nucleus andcontinuing the treatment with olefin to alkylate the sulphonic acidgroup, in the presence of an inert solvent for the aromatic body andolefin,

5. A process for producing alkylated sulphonated and esterified aromaticbodies which 5 consists in reacting an aromatic body with s phuric acidin excess of the amount required to produce the mono-sulphonic acid andwith an olefin in the presence of an inert solvent for the olefin andaromatic body, and continuing the olefin 10 treatment to alkylate thearomatic nucleus and to esterify the sulphonic acid group.

6. A process for sulphonating alkyla'ting and esteriiying an aromaticbody in a single operation which consists in mixing an aromatic bodywith 15 an inert solvent and sulphuric acid in excess of the amountrequired to produce mono-sulphonic acid and then adding an olefin tosaid mixture, whereby the aromatic nucleus is sulphonated and alkylated,and continuing the treatment with olefin 20 until the sulphonic acidgroup is esterified.

'7. A process for producing alkylated sul-, phonated and esterifiedaromatic bodies which consists in reacting an aromatic sulphonic acidwith an olefin in the presence of an inert solvent 25 and in the absenceof other acids and at a temperature of the order of C. to C.

8. A process for producing alkylated sulphonated and esterified aromaticbodies which consists in reacting an aromatic sulphonic acid 30 with anolefin in the presence of sulphuric acid to alkylate the aromaticnucleus and continuing the treatment with olefin to esterify the acid.

9. A process for producing alkyiated sulphonated and esterified aromaticbodies which 3 consists in reacting an aromatic sulphonic acid with anolefin in the presence of an inert solvent and sulphuric acid toalkylate the aromatic nucleus and continuing the olefin treatment toesterify the sulfonic acid group.

10. A process for producing alkylated sulphonated and esterifiedaromatic bodies which consists in sulphonating an aromatic body andreacting the sulphonated body with an olefin to alkylate the aromaticnucleus, then stopping the 45 reaction and further reacting thesulphonated and alkylated body with a different olefin to esterify thesulphonic acid group.

11. The process which consists in reacting a sulphonated aromatic bodywith excess sulphuric 0 acid and an olefinic material in the presence ofan inert solvent for said aromatic body and olefinic material toalkylate the aromatic nucleus and continuing the olefin treatment toesterify the sulphonic acid group.

12. The process which consists in reacting an aromatic body withsulphuric acid in excess of the amount required to produce themono-sulphonic acid and with an olefinic material in the presence of aninert solvent for said aromatic body 60 and olefinic material toalkylate the aromatic nucleus and continuing the olefin treatment toesterify the sulphonic acid group.

13. The process which consists in reacting a sulphonated aromatic bodywith an olefinic ma- 65 terial in the presence of an inert solvent forsaid body and material and in the absence of other free acid whilemaintaining a reaction temperature of the order of 80 C. to 120 C.

ROBERT M. ISHAM.

